Most present day EKG electrodes are of the disposable type and comprise a pad member with an electrode projection on its top surface and adhesive material on its bottom surface except for a central portion containing a conductive jelly for making good electrical contact with a patient's skin when the pad is pressed in place. A cable terminating in an electrode snap fastener is connected to the electrode projection on the pad so that proper electrical connection is effected. Several such disposable electrode pads are located at strategic positions on the patient's torso and small electrical signals indicative of the patient's heartbeat can be properly recorded to form an electrocardiogram for the patient.
After the electrocardiogram has been completed, the cable electrode snap fasteners are removed from the electrode projections on the electrode pad and these pads simply removed from the patient's torso and thrown away.
Problems currently experienced with present day EKG electrodes may be summarized as follows:
1. Artifacts (spurious signals) are caused by relative movement between the electrode projection and the electrode snap fastener resulting from movement of the lead wire or cable extending from the snap fastener. Such movement can be a result of the relatively long cables used in some instances as well as from the movements of the patient. PA1 2. Artifacts are also generated when the impedance between the metallic electrode projection and the patient's skin changes. Such impedance change is caused by an increased space between the skin and electrode projection when the lead wire or cable is pulling against the electrode. PA1 3. Patient movements often cause the breakage of lead wires due to tension. PA1 4. Because of the freedom of movement of the cable, there is wear on the cable and frequent replacement is often necessary.
The foregoing problems have plagued the hospital industry since the inception of disposable type electrodes. Attempts to solve these problems have taken the form of utilizing large quantities of adhesive tape to tape the lead wires or cables to the patient's torso. For example if portions of the cable extending from the snap electrode could be taped to the patient's torso it is clear that relative movements between the snap fastener and the electrode projection itself would be substantially reduced since movements of the remaining portions of the cable beyond those portions fastened to the patient's torso would have little effect on the connecting portions to the electrodes. However, utilizing conventional adhesive tape in this manner has brought along many new problems. For example, the large quantity of adhesive tape for each of the electrodes involved (and there may be 4-6 electrodes during any one recording session) obstructs other diagnostic procedures including defibrillation. Further, the adhesive tape itself is irritating to the patient and requires shaving of a large skin area if it is to be effective in adhering to the skin. This latter problem creates another problem in the increased cost and time for skin preparation. Finally, there is general discomfort to the patient when the various cables or lead wires are mass-taped to his skin.